JSP-719-90, Application for Amend to License DPF-62,revising Tech Spec 3/4.6.5, Drywell Post-LOCA Vacuum Relief Valves

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Application for Amend to License DPF-62,revising Tech Spec 3/4.6.5, Drywell Post-LOCA Vacuum Relief Valves
ML20059G570
Person / Time
Site: Clinton Constellation icon.png
Issue date: 08/31/1990
From: Jamila Perry
ILLINOIS POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20059G574 List:
References
JSP-0719-90, JSP-719-90, U-601276, NUDOCS 9009130024
Download: ML20059G570 (10)
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u CLINTON POWER STATION, P.O.130X 678. CLINTON. ILLINOIS 61727 0678. TELEPHONE (217) 935 8881 1 j

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. JSP-0719-90 g I+4 August- 31, 1990-I -.

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10CFR50.90 ,

Docket No.: 50-461' 4

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. Nuclear Ragulatory Commission i !

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' Document Control' Desk

. Washington,=D.C. -20555 4

Subject:

. Clinton Power Station Proposed Amendment of Facility. t

.Qppratina License No. NPF-62 L .

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Dear,

Sir::

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Pursuant to 10CFR50.90, Illinois Power (IP) hereby applies; '

for= amendment of' Facility Operating License No. NPF-62,.

p o < Appendix A - Technical Specifications,-for Clinton, Power-Station

!' i"" '(CPS). jThis request consists of proposed: chang'es to Technical 1 c1 Specification'.3/4.6.5, "Drywell Post-LOCA Vacuum Relief Valves." .;

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-A descriptiontof.the proposed changes and'~ associated  :

justification, including-a Basis.For No Significant Hazards

b. , , ' consideration, and marked-up copies-of pages-from the current '

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Technical Specifications and Bases, are provided-in Attachment-2.-.

, ~In addition,=an affidavit supporting the-facts; set forth~in-this j -letter and its attachments is provided:inLAttachment 1.

a L ' IP has reviewed the proposed-changes against'the criteria:of l L', '10CFR51.22'for: categorical' exclusion from'. environmental impact 77 ' ,-  ? consider.ations. LThe proposed changes,de not-involve'a1 (;

i , significant hazards consideration,
or: significantly increase the- ,

amountsfor; change thectypes of effluents that:may be' released 1

. loffsite,,nor do they significantly increase individual or

-cumulativeLoccupational radiation exposures. Based.on-the- r foregoing,!IP concludes:that the propose ( changes meet the 1 l  ! criteria- g'iven in 10CFR51. 22 (c) (9) for a categorical' exclusion' 3

[/> , from theLrequirement for'an. Environmental-Impact. Statement.

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, , Sincerely yours,.

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' N S. Per Vice President ,

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"; 9009130024 900831 ADOCK 05000461

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. Attachments cc: Regional ~Adminstrator, Region III; US.NRC NRC Clinton-Licensing Project Manager NRC Resident' Office Illinois Department o'J Nuclear Safety Ii h

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-Attachmsnt-1 . ,

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< STATE OF ILLINOIS i

'W COUNTY OF-DEWITT l,

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J. . Stephen Perry, being first duly. sworn, deposes and says: That f ~he is:Vice President of Illinois Power Company; that the Japplication:for amendment of Facility Operating License NPF-62 hac been prepared under his supervision and direction; that he L'.'

knows the contents thereof; and that to the best of his knowledge >

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P 'and belief said' application and the facts contained therein are .;

.:3 . 'true;and correct. .

,i DATED: This-3/ day of August 1990 Signed:- -

hl. SbePhenPegy i

b , subscribed and sworn to before me this 1 day of August" 1990.- r i

jltoA.fR [. hl0AkLD Notary Public

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"0FFICIAL SEAL" <

l-- r jl Sharon E. Harris ' ll Notary Public, State of Illinois ll J

i ,' My Commission Expires 3/9/91 ; ,

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- Attachmsnt 2'

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Attachment 2 The following package comprises' Attachment 2'.

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Page 1 of 10 Descrintion of Procosed Changes-m In accordance with 10CFR50.90, t.he following changes to Clinton Power Station (CPS)l Technical Specification-3/4.6.5, "Drywell Post-LOCA Vacuum Relief

- Valves," are being proposed:

1;- _

Action "a" is being revised to allow one or both closed drywell post.

Loss of Coolant Accident (1DCA) vacuum relief valve (s) in a single -

penetration to be inoperable for openin6 for up to'72. hours.

2.. Action "b" is being revised _to allow one or more drywell post-LOCA vacuum relief valve (s) to be open for a limited period 'of time._ This

_ proposed change will require that at least one drywell post-1DCA vacuum relief valve in each penetration (rather than all valves) be closed within one hour.

'3. Action."c" is being revised to allow the position indicator of one E R2Le drywell post LOCA vacuum relief valve (s) to be inoperable' provided at least one vacuum relief valve in each affected peretration'(rather:

than the valve with inoperable position indication) is verified to bc in=

m the closed position at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Additionally, an exception to the provisions.of Technical Specification 3.0.4 is'bein5 added to this Action Statement to allow plant mode changeu with inoperable position indicator (s).

4. A footnote (footnote "**") is being added'to the above Ac'tlon. Statements.

to allow drywell post-LOCA vacuum relief valves to be opened on an intermittent basis under- administrative control to perform required v surveillance testing or repairs when the-valve (s) is required to be maintained closed by the' Action Statements.

These proposed changes (including. proposed changes-to the associated Bases) are indicated on the attached marked up pages from the CPS Technical.

.Spe niications. (See pages 7, 9,.and 10 of this submittal package.)

Justification for Proposed Channes-W

.The CPS design incorporates eight drywell post LOCA vacuum relief valves.

These valves are arranged such that two valves are in series in'each of four

. separate drywell penetrations. Thus, both valves in a single penetration must

.open in order for the drywell atmosphere to communicate with the containment-atmosphere. The position of each vacuum relief valve is indicated in the main

control' room. These indicating lights are controlled by limit switches on the

' valves and indicate closed, intermediate, and open valve position. The indicating lights are powered from non divisional power. Additionally, each valve'is provided with an actuator which is used only during surveillance testing to verify the capability of the valve to fully open. These actuators are not required to function in order for the valve to perform its safety functions.

As described in CPS Updated Safety Analysis Report (USAR) Section 6.2, the drywell post LOCA vacuum relief valves perform two basic safety functions:

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'(1) The valves (i.e., the penetrations associated with.these valves) must remain closed during the blowdown phase of a postulat3d Loss of Coolant Accident (IDCA) in order to maistuin' drywell integrity. . l Drywell integrity is required in order lp minimize the amount of -

steam.that bypasses the suppression pool'and directly enters the containment atmosphere. 'If this steam bypass is-greatetcthan the >

W design' limit, overpressurization of the containment could, result ,

following a LOCA, ,

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-(2). The_ valves must open following iyicia'tipn of the drywell - d

, containment atmosphere mixing system cruvpressors' (which arei .

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! manually actuated approximately one L ur.after.a postulated LOCA) U 3: in order to ensure that the drywell and containment hydrogen

,,n qconcentration does not exceed the flammability < limit.

'It:should be noted.thatL(even though the valves are identified as "drywell L c post-LOCA vacuum relief valves") no credit is taken for operation of tho

~drywell. post;LOCA vacuum relief valves for limiting-the negative pressure of the drywell'following a LOCA. Analyses presented in USAR Section 6.2,1,1.4~,1- .

demonstrate that the drywell negative differential pressure design limit.7of 17 d pounds.per square inch differential (psid) is.not exceeded during a design.  ;

, ,, basis accident assuming-that the drywell post LOCA vacuum relief valves do not  ;

. 'open . . t A u? >- -

Additionally, : opening of the drywell post; LOCA vacuum relief valves -is f

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descrioed.in the containment negative pre'ssure evaluation presented inLUSAR m .

Section. 6.2.1.1.4.2. _(This analysis discusses a break in the Reactor _ Water Q,"o C1sanup-(RUCU) System piping inside the containment.followed by an inadvertent- ]'

i . initiation of;the containment spray system.) The opening of the drywell post '

LOCA' vacuum relief valves 'however, is'a conservative assumption to support-

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.this bounding,(conservative. analysis and is not required to mitigate-the ^j effectstof this event.

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,y Each 'of the proposed changes - and their impact on thc A,me safe y functions is l discussed below.

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!Pronosed Channes_to Action "a"- .i h 1 .

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o -Technical Specification 3.6.5 Action."a" addresses the conditiba in which a

- ory.;:11' post-LOCA vacuum relief valve is inoperable for oph&g but known to .)~

be closec. This Action Statement currently limig 4his tvpe d inoperability to one drywell post-LOCA vacuum relief valve W r 92 Scurs. Therefore, under the current' format,'if more than one vacuum relief valve is inoperable for

, :op'ening, entry;into Technical Specification 3.0.3 would be required and a ,

plantishutdown would have to be immediately initiated. The proposed change to

. Action "a" would allow one or both valves in a single penetration to be

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' inoperable for. opening since, with respect to the penetration, it effectively makes no difference whether one or both valves are incapable of opening. (The ,

. penetration is ipoperable either way with respectete supporting flow through the(penetration;) This proposed change will therefore preclude unnecessary entry into Technical Specification 3.0.3 while the safety basis for these valves is being maintained.

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  • Page 3 of 10 J This Action Statement is only. applicable to drywell post LOCA vacuum relief  !

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_ valves which are closed but not capable of opening at the required differential pressure. In this configuration, drywell integrity is maintained since the inoperable valve (s) is known to be. closed. Additionally, the safety-bases for opening are still/ maintained since only one penetration would be affected. However,-the redundancy provided in the system design has tc a reduced with ons Nacuum-relief penetration unavailable (to support 'h through the penetrations). Therefore, this Action Statement will t c. - mai the opening function of the inoperable penetration be restored .within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.1 This restoration rime is consistent with the current Actiot requirements when one penetration is not capable of opening because "e i . inoperable valve end is; justified based upon the low probability of an

, -additicnal failure occurring coincident with an-*.$nt requiring drywell vacuum relief valve operation during this time period.

7 Proposed Chances'to Action "b"

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1 Technica1' Specification 3.6.5 Action "b" addresses.the condition in which a drywell post-LOCA vacuum relief valve is open. This-Action Statement currently. limits this condition to ons drywell post-LDCA vacuum relief valve and' requires the valve to be closed within one hour. If more than one vacuum relief valve.is open, entry into Technical Specification 3.0.3 would be ..

required and a plant shutdown would have-to be immediately initiated. The j

, proposed change to Action "b"- would allow more than one vacuum relief valve to

= be open but would require that at least one vacuum relief valve in each

, penetration be closed within ene hour. This proposed change would thus

preclude unnecessary entry into Technical Epecification 3.0.3 and yet supports theLintent to. maintain the plant configuration co1sistent with the definition of DRWELL INTEGRITY.

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'Per Technical Specification 3.6.2.1, drywell-integrity must be maintained while in Operational Conditions 1, 2, and 3. In the event-drywell. integrity

.is not maintained, the Action Statement for Technical Specification 3.6.2.1 requires drywell-integrity to be restored within one hour'. Ensuring thatz at least one drywell vacuum relief valve in each penetration is closed within one hour serves.to restore drywell integrity within the time required by Technical ,

. Specification 3.6.2.1. It should also be noted that Technical Specification  !

o 3.6.2.2 requires that the drywell bypass leakage be limited to 10% of'che u acceptabledesignA/$fkvalueof1.18ft2 TheadditionalA/iIEareaofone J open' penetration is approximately 0.22 ft2 (approximately 18.4% of the design value). Therefore,. assuming that drywell bypass leakage-is initially:at the 10%,11mitofTechnicalSpecification3.6.2.2,thedesign-A/1hdlimitof1.18 ft2 : would not be exceeded, even with all four penetrations fully open. -As a result, the capability of the drywell to perform its safety function would be prese rved. The remaining functions of the drywell post LOCA vacuum relief valves would also be unaffected since these velves would remain capable of opening.

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y y . Pronosed Channs to Actioh "t"

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J Technical Specification 3.6.5 Action "c" addresses the condJlorm which a 'N's drywell post thCA vacuum relief valve position indicator is 'i toperai.le. This Action Statement currently limits this condition to one'drywell post-LOCA 0 ',h vacuum relief % 1ve and requires the valve to be verified to be closed at q l s.

least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> by visual inspection. trnder the current format, if '

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more than one vacuum relief valve position indicator is inoperable, entry into Technical Specificat. ion 3.0.3 would be required and a plant shutdown would have to be insediately initiated. The proposed change to Action "c" would ,

allow the position indication for any number of vacuum relief valves to be i inoperable as long'as at least one valve in each affected penetration is ,*

. verified to be closed at icost once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. .his would preclude  %

F unnecessary entry into Specification 3.0.. and thw potentially pht ent an y*

unnecessary plant shutdown. The requirement to verify that at leibt one W 1ve_ ,

in each affected penetration is closed would continue to provide confineneet g thct ear ln affecte;t penetration is closed for supporting drywe?1 integrity. -

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.Incddition,itisrecognizedthatinoperabilityofthepositioYi$dication alone does not affect the capability of the drywell post lema vacuunirelief valve (s) to perfsta its required function. (Regarding operability of the valve (s) with 1espect to its capability to open, successful prformance of 2

Surveillance Requfxement 4.6.5.b.2 verifies operability. Inoperability for opening is addressed by Action "a".) With respect to the valve full open position indication, the drywell vacuun relief valves are passivQ there is no operatre action involved in sin operation of these valves. Moreover, dther l' means exist to verify that tre valves'have opened to perform their o p n e i functions (combuntible gas contro) system operation and pressure reliefn d ~ ,

there are instrusevnt indications available for other applicable paraca n:i x K -

such as drywell and containment presn.co, drywell and containment hyd m gen t s levels, etc. Timre fere, the proposed revision to Action "c" is justitled an. -

it is also consistent with the curuenr Action "c" specified for tnoperable '

position indication for only one s.dve.

  • LT Thi> proposed change would al o hdd an exception to the provisions c# -

Technical Specification 3 A.4 to allow plant mode changes when a drywc11 pesta L LOCA vacuum relief ~ valve podi. tion indicator (s) is inoperable, As discvssed

  • above, inoperability of dqwil post LOCA vacuum telief valve positior.

l l: indication alone doeu noc cauw the affected valve to become tacapabl6 oi j

performingitsintendedfunctqus. Verification that the penot acit.n is % ,"

,  ; f l' closed at least once per 24 he'tra supports drywell inte6tity. Therefore, ni  !

is' overly restrictive to prohihit plant startup and mode changes when only 1.he  !

vacuum relief valve's position' indication is inoperable,

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{ } %' Page 5 of 10 Proposed Addition of Footnote "*** ,

y$ , Technte.a1 Specification 3.6.5 currently requires all eight drywell post IDCA hy 'i y' vacuunt relief valves to be operable and closed. As ~eviously discussed, the t 9 , CPC design incorporates two valves in series in four separate drywell i G peNtrations . In the event that any of these valves or position indicators

  • / s become inoperable. the proposed Action Statements require that the affected penetration be verified to be isolated by at least one drywell post lhCA i 4

y3 7 vacuum relief valve in the closed position. In the event that the affected i i valve (s) is the inboard valve, the outboard valve may be required to be opened g to allow visual. observation of inboard valve disk porition or operation. A '

e footnote has therefore been proposed (footnote ***") to allow opening a valve;(s)*, which may be required to be closed per the Action Statements, on an

," , j intermittent basis under administrative control to perform required  !

T surveillance testing or repairs. These administrative controls include

! limiting the use of this footnote only to perform required surveillances and '

! i necessary repairs, and minimizing the length of time a penetration is open.  ;

i Additionally, functional testing of the drywell containment atmosphere mixing

' compressors on a quarterly basis in accordance with Technical Specification

' Surveillance Raquirement 4,6,7.2.a causes these valves to open. The proposed  :

fo+; note will thus provide the required flexibility needed to maintain A com)11ance with Technical Specification 3.6.5 while performing surveillance '[

' testing required by Technical Specification 4.6.7.2.a. l L Brsis_for No S hnificant Harards Consideration l/ In accordance with 10CTR50.92, a proposed change to ths operating license l " (;

  • s(Iechnical Specifications) involves no significant hazards considerations if b,A operatiou of the facility in accordance with the prop.,se6 chan6e voald not:

.i'" 'R). involve . significant increase in the probability or consequences of any

m accident previously evaluated, or (2) create the possibility of a new or
h.  ! u ftfferent kind of accident from any accident previously ovaluated, or (3)

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,3 1nvolyn a significant reduction in a margin of safety. The proposed changos ure w aluated against each of these criteria below. '

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  1. (11. With the proposed changes, the Tochnical Specifications will still '

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ensure that.the drywell post LOCA vacuum relief valves can perform their l'

< required safety funct!.ons. Specifically, the revised Action "a" would

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's:till ensure that tM minimum number of valves / penetrations remain avat:able to perform the opening functions of these valves / penetrations;

sevised Actions "b" and 'c" and the proposed footnote "**" would still t ensure that each drywell vacuum relief penetration is sufficiently 3 closed to maintain the drywell bypass leakage within the limits of the C <

. plant design and the current Action Statements for DRWELL INTEGRITY. ,!

N1 As a result, plant operation would continue to be maintained within the l bounds of the current safety analyses. Therefore, these proposed

% ~c hanges do not result in a significant increase in the probability or N' the wnsoquences of any accident previously evaluated.

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  • As ststed above, the additional A/ f area af one open penetration is '

c p roximately 0.22 f 2 As a result, even with all four penetrations fully vpon, the design A/ k limit of 1.18 ft2 would not be exceeded.  !

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(2) The proposed changes do not involve any change to the plant design.

Therefore, no new failure modes are involved, and plant operation continues to be limited to the bounds of the current safety analyses.

As a result, these proposed changes cannot create the possibility of a new or different kind of accident from any accident previously evaluated.

(3) The incorporation of the proposed changes into the Technical i Specifications will not adversely impact the capability of the drywell post-LOCA vacuum relief valves to perform their reruired safety g ,

functions. Additionally, plant operation will cr.ntinue to be limited to the bounds of the current safety analyses. Therefore, these proposed changes do not involve a significant reduction '.n a margin of safety. 3 Based upon the foregoing, Ip concludes that these proposed changes involve no 'f significant hnzards considerations. #

Procosed Bases Changes t

The current Bases for Technical Specification 3/4.6.5 do not reflect that USAR-  ;

Section 6.2.1.1.4.1 does not take credit for operation of the drywell post.  !

LOCA vacuum relief vr.1ves in uitigating the negative pressure effects on the 1 drywell following a design basis accident. The analyses presented in USAR Section 6.2.1.1.4.1 demonr : rate that the drywell negative pressure design limit is not exceeded during this event when the drywell post LOCA vacuum i relief valves are assumed to remain closed.

-Additionally, the current Bases for Technical Specification 3/4,6.5 do not. -

acknowledge that opening of these valves is required to support operation of -

the drywell containment atmosphere mixing system in maintaining hydrogen concentrations below the flammability limit as described in USAR Section 6.2.5.1.2.2. ..

Therefore, the Bases for Technical Specification 3/4.6.5 are being revised to -

L correctly address the applicable safety functions. Further, additional '

information regarding the configuration of these velves has been added to the D Bases.- ,

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